Process of producing treads



Patented Feb. 26, 1929.

't UNITED STATES PATENT OFFICE.

LEON B. CONALNT, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR, yBY MESNEASSIGN- MENTS, TO STANDARD PATENT PROCESS CORPORATION, A CORPORATION FMASSA- CHUSETTS.

Application filed July 5,

The object of this invention is the effecting of simple but effectivemeans for vulcanizing a rubber tread t0 a fibrous member of leather orcompressed fibre and the like. In

accomplishing this, I provide the fibrous member with numerous holestherein, whereby, upon vulcanizing the rubber composltion thereto, theplugs of rubber vulcanlzed'therein will strongly resist any pull tendinto separate the tread from the fibrous mem er.

In addition, I so roughen the inner surfaces of these holes'as to stillmore strongly bind together the tread and fibrous member.

In the drawings forming part of this specific-ation, Fig. 1 is a crosssection of a tread embodying my improvements. Fig. 2 is a cross sectionof a fibrous member previous to the vulcanization of the rubber treadthereto. Fi 3 is a sectional view of a die and punch suc as may be usedin perforating the brons member. Fig. 4 is a magnified sectional view ofa portion of the fibrous member showing rough walled hole.

As shown in Fig. 2, aK fibrous member 1 a5 composed of leather or othersuitable ma terial, is provided with a plurality of holes 2 formed inany way therein, but preferably punched through it near its marginalportions. As illustrated in Figs. 1 and 2, these 3o holes are disposedin groups of two, while in Fig. 4 one hole alone-is shown at aparticularI location having its interior rough and ragged asillustrated.

Previous to my invention the only way in which leather was erforated wasby means of hollow punches orced through the leather upon a woodenblock. This method always resulted in forming entirely .smooth holes.

But I have discovered thatby using solidv punches 3 co-operating femaledies 4, the holes formed thereby were very rough, with the intersticesand fibrous projections in the surfaces of the holes most pronounced.Into 1924. Serial No. 724,340.

these sc abrous or rough surfaces the rubber composition is intimatelyinjected duriiig the process of vulcanization. This roughness serves tobind the rubber plugs 11 of the tread 10 more securely therein, so thatthey cannot, without the exertion of considerable force exerted forlthat special purpose, be Withdrawn therefrom and the tread 10separated.

from the fibrous member 1. v

A suitable biscuit of rubber gum being' placed in the mold providedtherefor', and the perforate fibrous member 1 placed upon the gum, thecombined heat and pressure given in -a well known manner to the moldwill force the gum into its desired treadforni and up into the holes 2,and t-hen vulcanize the same therein. A

When the plugs 11 are vulcanized into ob'- liquely disposed holes 2,such obli uity adds very largely to the strength of pul required toseparate the tread from the lift, so that this, supplemented by theroughness of the holes, renders the rubber incapable under ordinaryconditions of use of becoming detached from the fibrous member. l

It is understood that the vulcanized combination of fibrous member andrubber tread is to be attached to a boot or shoe in any well knownmanner. Y

lVhat I claim as my invention is:

The process of producing combination treads consisting in providing thefibrous members with holes having scabrous surfaces, and then by meansof heat and' pressure vulcanizing a rubber tread thereto, the rubberbeing made to intimately engage said scabrous surfaces and thereby tobind the treads and fibrous members strongly together.

In testimony that I claim the foregoing invention, lI have hereunto setmy hand this 2nd day of July, 1924.

LEON B. ooNANT,

